Asphalt emulsions



Patented Jan. 22, 1935 I l UNITED STATES PATENT OFFICE ASPHALT EMULSION S Herbert M. Steininger, Kansas City, Mo., assignor to Standard Oil Company (Indiana), Chicago, 111., a corporation of Indiana No Drawing. Application October 1, 1930 Serial No. 485,823

10 Claims. (Cl. 134-1) This invention relates to asphalt emulsions 31 cc. of oleic acid therein. In a separate con and the method of making them, and it pertainer I dissolve 12 cc. of triethanolamine in tains more particularly to the activation of 1400 cc. of a tenth molarsolution of sodium sulemulsifying soaps by means of certain salts. phite. The triethanolamine solution is placed The object of my invention is to reduce the in amixer and brought toa temperature of about 5 necessary amount of emulsifying agents and to 175 F. The mixer is then brought to a speed thereby reduce the cost of emulsions. A further of about 600 R. P. M. and the hot asphalt is object is to expedite emulsification and to inslowly added thereto and emulsified in the aque crease the ease of emulsification. A further obthis solution. After all of the asphalt has been ject is to provide a fiuid emulsion containing a added, the emulsion is beaten for five minutes 10 high percent of asphalt, which emulsion will at 600 R. P. M. and then is beaten for another be stable at excessively high and low temperatures five minutes at 1200 R. P. M. Atthe-end of this and will be characterized by extreme smoothness time the emulsion is drawn off into a can or and small particle size. a suitable storage receptacle.

15 A further object is to provide an asphalt From the above description it will be seen that 15 emulsion having new and useful viscosity charmy formula is approximately as follows: acteristics. Other objects will be apparent from the following description. Percent bywelght Asphalt 63.56

I have discovered that with soap emulsifying Water 34 00 agents the interracial tension between the aque- 01610 20 bus phase and the asphalt is reduced to a. marked Triethanolgige degree by the presence of certain amounts of Sodium sulphite mineral salts. The best results are obtained when the finished emulsion is kept neutral or The beater 1 mixer may be 0f a y Suitable basic, but alkalinity isnot the only factor con- Construction- I e found at 1 making 25 trolling the ease of emulsification. When 0.1 Small batches, a Small Cylinder about 8 or 12 molar solutions of sodium sulphite, potassium in. in diameter and about 15 in. de p be chromate, sodium carbonate, etc., are substid d w t a t r p at ds r hav tuted for water in the preparation of emulsions tW0 to T0111 blades about 4 lOIlg and three with soaps (particularly triethanolamine oleate) fourths Of an inch wi e, Suitable Stat onary blades 30 I have discovered that the amount of emulsifyand bafllos e n p v d d pr v n cycl nic moing agent may be reduced t l th one-half tion in the mixer. The device may be surrounded the amount heretofore. required; that the reby a Steam J k m y be q pped with other sulting emulsion is fluidat lower temperatures means for C ll emp ratures.

- as and with greater amounts of asphalt, and that Wh n w parts of p al ar mulsifiedin one the emulsion is more stable and more permanent P -r Of at i triethanolamine than emulsions formed in the absence of. dilute fi e fi is. qu d for Ob a ing'a suitable emulsalt solutions. My invention will be more clearly si W h o amountof p al s mulunderstood from the following description wheres fied i a tenth molalisollltion of So sulphite, 40 in I have set forth in detail a preferred embodia satisfa y emu n e t d wit nly t th f, 1.0% of triethanolamine oleate. Furthermore, the

. hil th underlying principles of my invenemulsion produced with the dilute salt solution is ti are n t limit d to any particular asphalt much more fluid and is characterized by a much (bitumen), emulsifier, or salt, I have described Smaller particle SiZey using di ute salt $0111- an emulsion made from specific ingredients. tions I obtain asphalt emulsions containing from 45 The asphalt may be an oxidized petroleum residto asphalt Which are fluid at room temuum having a penetration of 60 to '70 at 77 F., perature; when using no salt, the emulsions solidhaving a melting point (ball and. ring method) ify at room temperature even when 2.4% of triof about F., a specific gravity of about 1.00 ethanolamine oleate is employed at the same 50 and a fiash of about 460 F. In my preferred speeds and temperatures of mixing. 50 embodiment I use a hydroxyalkylamine soap, I have found that emulsions made with an alsuch as triethanolamine oleate or stearate as an kali metal chromate or sulphite are more stable emulsifier. than those produced from other salts-such I heat 2556 grams of the asphalt to a temperaemulsions have been heated to the boiling point 56 ture of about 250 F. and incorporate or dissolve of water without breaking. The presence of so- 55 7 cases, due to the oxygen in the salt).

diumsulphite also has the remarkable effect of preventing scum formation.

Emulsions prepared in dilute sodium carbonate solutions exhibit peculiar temperature viscosity characteristics. When the asphalt is emulsified in a tenth molar sodium carbonate solution by about 1% of triethanolamine oleate, the viscosity of the emulsion decreases with increasing temperature up to a certain point, and then as the temperature increases the viscosity again increases. A similar effect is produced when the emulsions are prepared in a dilute solution of sodium hydroxide. At temperature of about '70 to 80 F. the sodium carbonate solution emulsions are much more viscous than sodium sulphite solution emulsions. The viscosity of the latter gradually increases with decreasing temperature. The viscosity of the former decreases to a minimum at about 40-50 F. and it then increases as the temperature continues to fall.

The most satisfactory emulsions from the standpoint of stability, ease of emulsification, fluidity, and character of residue (on evaporation of the water) are emulsions prepared in dilute solutions of salts, such as sodium sulphite, and sodium or potassium chromate. Other salts, such as sodium oxalate, trisodium phosphate, sodium sulphide and sodium thiosulphate, have given satisi'actory results. In all cases, the salts added must be neutral or alkaline and an emulsion may be prepared by dispersing asphalt in a dilute solution of sodium hydroxide or spent caustic by means of triethanolamine oleate.

If it is desired toadd a mineral filler, such as kaolin, fullers earth, bentonite, or other colloidal material, the acidity of these clays must be neutralized by an alkali or an alkaline salt.

WhileI have described the use of oleic acid, I donotlimit myself thereto and stearic acid or other equivalents may be substituted therefor. The residue from a stearic. acid emulsion has a lower penetration than the same asphalt emulsitied with oleic acid.

As above stated, the most satisfactory emulsions are produced by using potassium chromate and sodium sulphite. It would appear that the oxygen in these salts may have some effect on the asphalt emulsification. There are apparently at least three factors which contribute to the activating action of these salts on triethanolamine soap emulsifiers: (1) They decrease the interfacial tension between the asphalt and the water; (2) They maintain a proper alkalinity and (3) They exert a'catalytic effect (probably, in some It is believed that the'addition of the alkaline salt will decrease the interfacial tension between the asphalt and the water .to about one-fiftieth of its normal value. Triethanolaminesoaps are slightly alkaline, and by using the salts I greatly reduce the required amounts of triethanolamine and at thesame time I retain'the advantages heretofore obtained with an excess of the reagent.

All grades of asphalt manufactured from Winkler and Mid-Continent crudes have been successfully emulsified by my improved process, and it is known that these bitumens are more difficult to emulsify than are ordinary tars and asphalts. The remarkable influence of the salt solutions, as hereinabove described, has been noted with ordinary soaps such as sodium oleate and commercial soap chips. It will be apparent, then, that while I have described my invention by giving a preferred embodiment thereof, it is understood that the invention is applicable to other bitumens soaps and salts, and that my invention is not limited to the details above set forth except as defined by the following claims:

I claim:

1. The method of preparing an emulsion which comprises emulsifying an asphalt with triethanolamine oleate in a dilute aqueous solution of a water-soluble salt having a neutral to basic reaction whereby the salt reduces the interfacial tension between the water and the asphalt.

2. The method of preparing a fluid, stable emulsion which comprises emulsifying bitumen with a hydroxyalkylamine soap in a dilute aqueous solution of a Water-soluble salt having a neutral to basic reaction whereby the interfacial tension between the water and the bitumen is reduced by the salt.

3. The method of preparing an emulsion which comprises emulsifying a bitumen with an ethanolamine soap in the presence of a dilute aqueous solution of an oxygen-containing water-soluble salt having a neutral to basic reaction.

4. The method of claim 3 wherein the salt is sodium sulphite.

5. The method of claim 3 wherein the salt is an alkali metal chromate.

6. An emulsion comprising about two parts of asphalt, one part of water, 1% triethanolamine oleate, and a sufficient amount of a water-soluble salt having a neutral to basic reaction to give about a 0.1 molar solution in said water.

' '7. An asphalt emulsion containing about two parts of asphalt emulsified in one part of water by meansof about 1.0% of triethanolamine oleate activated by a fraction of 1% of a water soluble oxidizing salt having a neutral to basic reaction.

8." The method of emulsifying asphalt which comprises incorporating fatty acid in said asphalt, incorporating less than 1% of triethanolamine, based on finished emulsion, in a dilute aqueous solution of a water-soluble salt having a neutral to basic reaction, and mixing said asphalt mixture with said solution.

9. The method of claim 8 wherein the salt is sodium sulphite.

10. The method of claim 8 wherein the salt is an alkali metal chromate.

HERBERT M. STEININGER.

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